Cover crops (CC)s are increasingly employed by farmers in olive groves. Spontaneous
soil cover is the most commonly used CC. Its continuous utilization changes ruderal flora. It is
necessary to study new CCs. Living CCs provide C and nutrients to soil during decomposition.
Information on this issue in olive groves is scarce. A 4-year field study involving grab sampling of
Brachypodium distachyon, Sinapis alba and spontaneous CC residues was conducted to study C and
nutrient release from cover crop residues. Throughout the decomposition cycles, C, N and P release
accounted for 40 to 58% of the C, N and P amounts in the residues after mowing. Most K was released
(80–90%). Expressed in kg per hectare, the release of C and N in Brachypodium (C: 4602, N: 181, P: 29,
K: 231) and Sinapis (C: 4806, N: 152, P: 18, K: 195) was greater than that in spontaneous CC (C: 3115,
N: 138, P: 21, K: 256). The opposite results were observed for K. The Rickman model, employed to
estimate the amount of C, N and P in residues, yielded a good match between the simulated and
measured values. In comparison to spontaneous CC, the newly proposed CCs have a higher potential
to provide soil with C and N
